Preferential oxidation of Si in SiGe for shaping Ge-rich SiGe gate stacks

The oxidation of SiGe is quite different from that of Si or Ge. By paying attention to the oxidation kinetics of SiGe, a gate stack formation guideline on SiGe is proposed. Based on the understanding of oxidation kinetics, we design the gate stack formation process and demonstrate very good C-V characteristics on SiGe with Si-cap free passivation, by direct deposition of a designed dielectric film, followed by an optimal post-deposition annealing.